MED6 (mediator complex subunit 6) is a conserved component of the Mediator complex, a critical coactivator that regulates RNA polymerase II-dependent transcription 1. Structurally, MED6 is part of the Mediator head module and forms specific interactions with the RNA polymerase II C-terminal domain (CTD), particularly binding between the Med6 shoulder domain and Med31 knob domain to facilitate transcriptional regulation 2. Functionally, MED6 plays essential roles in transcriptional control and cellular metabolism, as its silencing leads to increased lipid droplet accumulation and upregulation of lipid metabolism genes PLIN2 and DGAT1 3. In pathological contexts, MED6 is required for HIV-1 transcription, with its knockdown significantly impairing viral replication and early HIV transcript formation 4. Clinically, MED6 shows aberrant high expression in hepatocellular carcinoma and correlates with pathological staging and immune cell infiltration 5. The protein has also been identified as a potential diagnostic biomarker for both Alzheimer's disease and metabolic syndrome through machine learning approaches 6. These findings establish MED6 as a multifunctional transcriptional regulator with significant roles in normal cellular processes and disease pathogenesis.